Chromatography is a technique for separating compounds, such as those held in solution, where the compounds will exhibit different affinity for a separation medium in contact with the solution. As the solution flows through such an immobile separation medium, the compounds separate from one another. Common chromatographic separation instruments include liquid chromatography (LC) systems. Such LC systems are known and used for analyzing sample solutions that may include different chemical compounds. LC systems may operate at high pressures such as at 5,000 PSI and greater. A typical LC system includes a pump for pumping a liquid solution, an injector for injecting the sample into the liquid fluid stream, a chromatography column packed with packing material used as the separation medium and tubing for carrying the sample solution and liquid fluid from the injector to the chromatography column. The tubing may then be used to further transport the sample solution output from the LC column to a detector for analyzing the sample solution. The detector may be any suitable detector such as a mass spectrometer, a UV absorbance detector, an evaporative light scattering detector, and the like.
During operation of the LC system, a liquid solvent is pumped into the LC system at high pressure. The injector may be used to inject controlled volumes of a sample, either manually or automatically, into the system where the sample is carried with the liquid solvent in a fluid stream to the packed LC column where the sample may then be separated. Because each of the chemical compounds in the sample solution react in a different manner with the LC column packing material, the various chemical compounds flow through the packed LC column at different rates. The different chemical compounds in the sample solution separate from each other as the sample solution flows through the column. The separated chemical compounds as output from the LC column proceed to the detector where they may be further analyzed, for example, to determine physical characteristics of the compounds for purposes of identification and/or quantification.